Testing is a key operation of semiconductor fabrication. To facilitate testing on numerous semiconductor devices (e.g., chips or dies) on a wafer at the same time, probe cards are used. A probe card includes probes that correspond to contact pads on the wafer for the semiconductor devices.
Each of the semiconductor devices has contact pads accessed for testing. To allow for more contact pads connected to the semiconductor devices, wafer level chip scale package (WLCSP) was developed. In the WLCSP technology, the semiconductor device is packaged on the wafer level. By using the WLCSPs and the probe cards, the semiconductor devices are tested more effectively with an automated test equipment (ATE).